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Two things the 60 fps work needed, and one ceiling it found. Rectangle blit: a strip frame with stretch 1 has one source row per screen row, so the source advances by 1280 bits and a group of rows inside one fragment is contiguous -- one PIXBLT with SPTCH = 1280 copies the group. Measured on the tile path, a blit call costs ~0.45 ms in MAME regardless of size (1,200 tile calls accepted 9 frames where 128 strip calls accepted 73 for the same pixels), so call count, not word count, is what a frame is charged for. paint_rect() takes the stretch-1 frame 9 rows at a time and falls back to the per-row path if a row straddles a datagram. Ring depth: vidsrc still said RING_DATAGRAMS = 16 and capped a strip frame at 144 rows, which stopped being true when the receive ring was deepened to 32 for the dictionary upload. It is 32 now, the encoder may send up to the header's 255 rows, and the three tests that encoded the old ceiling were updated to it. The ceiling this found: a picture-as-strips full frame is 29 datagrams, i.e. 1,740 datagrams/s at 60 fps, while the emulated LANCE delivers ~450/s (1,935 datagrams over 4.3 s, measured). So keyframes cannot be sent as whole strips at 60 fps in MAME whatever the decoder does -- the datagram rate binds first. The tile delta (about one datagram a frame) remains the right transport; what costs is its blit-call count. Verified: modes rx, draw and tiles still PASS (draw and tiles with their pixel checkers); 155 unit tests pass.